Build: Nano Long Range 3″ FPV Drone Using 1S 18650

I saw this interesting 1S 3-inch FPV drone using 18650 Li-Ion cell for long range, and I had to give it a try. I will share my rather unsuccessful attempt and what you can learn from my experience if you want to build this too.

I love the idea that you can just snap a 18650 battery in this quad and fly for a very long time (20 minutes or more) :) And it’s super light too, only about 50g without battery. But don’t expect great flight performance, because it doesn’t. It’s slow and doesn’t have punch. It’s designed purely for staying in the air for a long time.

New to long range? Check out my tips on long range FPV flying.

Frame

Original design by Dave_C_FPV: https://www.thingiverse.com/thing:4769576

I am using this remix of the original frame, so I don’t need the battery tray (to save weight and cost): https://www.thingiverse.com/thing:4786123

The remixed frame needs battery contacts (with dimension 13.5×11.5mm), something like these: https://amzn.to/31n6iQc (Update: these have too much resistance, read my build update to learn about the issue)

Parts List

Recommended parts list:

I used the following parts instead, simply because I already have them, not because they are better:

Wiring Diagram

Credit to DaveC for this wiring diagram.

Build Updates

It took me around 6 hours to build this nano long range 3-inch, it was the soldering and figuring out how to mount everything in the limited space that took the longest.

Soldering these tiny components can be a bit challenging and requires steady hands and good solder tools :) Check out my recommended soldering tools here.

The weight is about 50g without 18650 cell.

My first attempt wasn’t successful though, the quad didn’t have enough power and couldn’t even lift off the ground. My first suspicion was the battery spring that isn’t good enough to deliver power from the 18650.

So instead of soldering the wire to the little tab, I soldered it right in the centre of the plate and the tip of the spring, the wires now have directly contact with the battery’s terminals, this should minimize resistance.

Or you could try this sort of battery contact which has much better performance, but i am not sure if you need to modify the frame or not: https://amzn.to/3tTTkWr (Keystone 209 1 Cell Leaf Spring Battery Contact, Nickel plated)

And that was kind of a success, the quad can now hover! It hovers at about 50%-55% throttle and it actually flies slightly better than I thought.

However, as soon as I move the throttle too quickly, the quad always drops out of the sky, and I could hear the ESC restarting chirp.

To investigate, I tried a normal 1S 300mAh LiPo on this quad, and it flies just fine! No more drop out.

So two possible causes for this problem I think:

  1. the 18650 battery I am using isn’t good enough (unlikely)
  2. the iFlight AIO FC can’t handle the voltage sag/fluctuations of the 18650 (more likely)

I am going to get some brand new VTC5A and try again just in case. In the meantime, I have also ordered the exact same HGLRC Zeus5 1S AIO FC that Dave_C used in his build, if the new 18650 doesn’t work then I will replace the FC.

Update (25/03/2020): I tried to update the ESC firmware tonight (downgrade actually, it was on 16.80, and I wanted to put 16.73 on it), but somehow it “bricked” the ESC, and now they won’t do anything when I plug in the LiPo, I also get “Flash Failed” error when I try re-flash them. Probably dead dead. Guess I will be replacing the FC after all :)

Stay tuned for more :)

8 thoughts on “Build: Nano Long Range 3″ FPV Drone Using 1S 18650

  1. Geniack

    That’s what I thought first too… I already had a step down regulator in there but have thrown it out. I am running the VTX (eachine nano v2) at 400 mW and everything seems very stable this way. This baby flies around 12 to 14 minutes, depending on the wind… As soon as voltage drops below 3 V the video gets worse but its still flyable until the voltage is so low that the quad basically drops out of the sky. So I think more powerful VTX’s might need an extra regulator but it’s not necessary always. This thing weighs in at about 120 grams with battery so Dave_C his first build at about 98 grams (the one with the carbon fibre frame) still managed to be lighter.

    Thank you for the build compliment!

    Reply
  2. Denis

    “Flash failed” when flashing the ESC often comes from using not fully charged battery. It is 100% with 4S, I dont know how it is at 1S. May be you should try flashing from DC power of exactly 4.20 or 5V…

    Reply
    1. Oscar Post author

      The ESC doesn’t respond at all now when I plug in the LiPo, looks like the MCU is either “bricked” or died.

      Reply
  3. Geniack

    Hello Oscar,

    I just finished my version of this build, using a carbon fibre frame instead. Do you have any idea why Dave_C is using a step up regulator in his wiring when the Zeus 5 AIO board he is using delivers 5V ? I didn’t find any specs on how much current the 5V out delivers, so there might be that. I have the issue that I have video drop outs the closer the voltage comes to 3.00 V while flying, maybe it would help with that? I also have the problem that the quad sometimes just falls out of the air but after restarting the flight controller it will continue to fly longer.

    Here is a picture for you:ibb.co/qWdXkdW

    Reply
    1. Oscar Post author

      The 5V on the FC isn’t very powerful and the VTX can draw way over 500mA so it’s best to have a separate voltage regulator for the VTX.
      Nice build you got there!

      Reply

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